public class MergeTwoLists {

    /**
     * 输入两个递增排序的链表，合并这两个链表并使新链表中的节点仍然是递增排序的。
     * @param l1
     * @param l2
     * @return
     */
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode dump = new ListNode(0);
        ListNode cur =dump;
        while (l1!=null&&l2!=null){
            if (l1.val<l2.val){
                cur.next =l1;
                l1 = l1.next;
            }else {
                cur.next = l2;
                l2 = l2.next;
            }
            cur = cur.next;
        }
        cur.next = l1!=null?l1:l2;
        return dump.next;


    }
}
